On December 5, Canonical published in a security notice details about a CUPS vulnerability for its Ubuntu 12.10 (Quantal Quetzal), Ubuntu 12.04 LTS (Precise Pangolin), Ubuntu 11.10 (Oneiric Ocelot), Ubuntu 10.04 LTS (Lucid Lynx), and Ubuntu 8.04 LTS (Hardy Heron) operating systems.
According to Canonical, CUPS could be made to read files or run programs as an administrator.
It was discovered that users in the lpadmin group could have modified certain CUPS configuration options to escalate privileges.
An attacker could have used this issue to potentially gain root privileges. For a more detailed description of the security problems, you can visit Canonical's security notification.
Users can simply fix the security flaws by upgrading the operating systems to the latest cups, specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. A complete system restart is not necessary.